DESCRIPTION (adapted from the application): Entamoeba histolytica, the cause of amebic liver abscess and amebic dysentery represents a significant threat to public health worldwide. The overall goal of this application is to develop a vaccine to prevent amebic liver abscess and colitis based on the E. histolytica Gal/GalNac lectin in the form of an edible plant-based delivery system. Extensive studies, including many from Dr. Petri's laboratory have identified the lectin as a major surface antigen of ameba, and demonstrated that it appears to play a critical role in amebic adherence, signaling, and complement resistance. Recent studies have identified the putative carbohydrate-binding domain of the lectin, and the proposed vaccine studies are built around this region. The application is divided into three projects, a laboratory core and an administrative core. In Project 1, recombinant peptides, which are built around the carbohydratebinding domain, will be expressed, purified, and tested for immunogenicity and protective efficacy. In Project 2, recombinant CRD containing peptides will be expressed in edible plants. In Project 3, the applicants will attempt to develop a novel adjuvant, based on the ricin B subunit to improve the immunogenicity of proteins in plants.